Sail rig for a wind driven craft

ABSTRACT

A sail rig for a wind driven craft comprising a rotatable gantry mast adapted to support one or more sails within the gantry and a support structure connected to said mast to rotate therewith and which carries an aft sail attachment boom which is pivoted to the support structure at a first end and provided with means for attachment to the clew of the sail or one of the sails at its second end, and a means for controlling the relative angle of the attachment boom in relation to the supporting structure.

[0001] This invention relates to a sail rig for a wind driven craft and a craft incorporating such a rig.

[0002] The term “wind driven craft” used herein is intended to apply to any vehicle which is driven by the wind and employs a sail or sails, for example a sailing boat, ice-yacht, land-yacht, or a vehicle mounted on rails.

[0003] According to the present invention a sail rig for a wind driven craft comprises a rotatable gantry mast adapted to support one or more sails within the gantry and a support structure connected to said mast to rotate therewith and which carries an aft sail attachment boom which is pivoted to the support structure at a first end and provided with means for attachment to the clew of the sail or one of the sails at its second end, and a means for controlling the relative angle of the attachment boom in relation to the supporting structure.

[0004] When a single sail is employed the support structure can be provided with fore and aft sail attachment booms each of which is pivoted to the support structure at a first end and provided with means for attachment to the appropriate tack or clew of the sail at their respective second ends, and means can be provided for controlling the relative angle of each attachment boom in relation to the supporting structure.

[0005] Thus, when attached to the whole or main structure of the craft the mast can be rotated on the turntable and the sail can either be stretched flat so that it has no aerofoil shape or the attachment boom can be pivoted to positions to induce a variable curvature in the sail. Moreover the exact positions of the leach and in the second construction the luff and leach of the sail can be adjusted in accordance with the wind strength or as desired.

[0006] Preferably the supporting structure includes a rotatable turntable for attachment to the craft with which it is to be used and on which the gantry mast is supported and the attachment booms are carried.

[0007] The structure can be arranged so that the gantry mast can be rotated through 36020 thus allowing the craft to be sailed backwards.

[0008] In a preferred construction the gantry mast has four legs, two on each side of the sail. Because of the stability imparted by this construction, no supporting or standing rigging is required such as would be needed for an orthodox mast.

[0009] In order to retain the sail in the desired position within the mast the sail can be provided with a flexible internal spine which extends between the upper part of the mast and the centre of rotation at the foot thereof.

[0010] The invention also includes a wind driven craft provided with such a sail rig.

[0011] The invention can be performed in various ways but two embodiments will now be described by way of example and with reference to the accompanying drawings in which :

[0012]FIG. 1 is a side view of a sailing craft in the form of a sailing boat provided with the sail rig according to the invention;

[0013]FIG. 2 is a front view of the sail rig and craft shown in FIG. 1;

[0014]FIG. 3 is a plan view of the craft with the sail stretched flat and head to wind;

[0015]FIG. 4 is a plan view showing the sail carrying a curvature for reaching with the wind on the beam; and,

[0016]FIG. 5 is a side view of a sailing craft provided with two sails.

[0017] As shown in the drawings the sail rig is mounted on a sailing boat the hull of which is indicated by reference numeral 1 and having a bow 2 and a stern 3. The sail rig comprises a rotatable gantry mast 4 which is adapted to support a single fully battened sail 5, the battens being indicated by reference numeral 6. The head of the sail has a short gaff 7 and the tack 8 and clew 9 are attached in a manner to be described.

[0018] The mast has four legs 10, two on each side of the sail, and the foot of each leg is attached to a turntable structure 11 carried on a circular track 12 which is secured to the hull 1 by struts 13.

[0019] A vertical shaft 14 is carried on bearings 15 provided on the hull and the turntable structure 11 comprises a circular mounting ring from which a pair of angled struts 16 extend upwardly to join a pair of support members 17, the inner ends of which are secured to the vertical shaft 14 and the outer ends of which carry pivoted attachment booms 18, 19. These attachment booms can be in the form of metal tubes, the fore attachment boom 18 being pivoted to the member 17 at a pivot 20 and the aft attachment boom 19 being pivoted to the support 17 at 21.

[0020] The tack 8 of the sail is connected to the outer end of the fore attachment boom 18 and the clew 9 of the sail 5 is attached to the outer end of the aft attachment boom 19 as shown in FIG. 1.

[0021] The sail 5 is provided with a flexible internal spine 23 the upper end of which is attached by a halyard to a gantry saddle and crown post 24 on the mast and the foot is secured to the shaft 14. Thus the sail is carried centrally in the mast and is attached to the top and bottom of the mast at a desired datum point in its width.

[0022] Such an arrangement facilitates the employment of a double surfaced soft sail.

[0023] The gaff 7 is carried by a halyard 25 to maintain it in the desired position.

[0024] The mast can be made of any suitable material, for example a metal (aluminium), or a suitably reinforced synthetic plastics material, for example carbon fibre, and a similar type of material can be used for the support structure.

[0025] The mast legs may be of tubular section allowing halyards and other rigging lines to be passed through them. This, coupled with the absence of standing rigging to support the mast, and the facility for the sail to be hoisted without requiring attachment to a central mast, results in disturbance to air flow around the sail being reduced.

[0026] Suitable operating lines are provided to control the amount of rotation of the mast and the amount of relative rotation of the attachment booms 18, 19 in relation to the support structure. The arrangement of such controls will be clear to any skilled operator of sailing craft and will not therefore be described further herein.

[0027] In a preferred arrangement, these operating lines are led to two winches located at the steering position. One winch controls the rotation of the rig and the other the relative rotation of the attachment booms 18, 19. This enables the essential sail settings and the course to be controlled by a single person from one position, adding greatly to the comfort, convenience and overall efficiency as compared to that afforded by orthodox rigs and considerably facilitating single-handed sailing.

[0028] At any point of sailing the amount of rig rotation can be controlled. This is achieved by selecting the rig (°) angle of incidence to wind direction. In order to sail the rig is rotated to a selected angle and adjusted to produce maximum forward thrust on the course being sailed. Because of the construction described above the rig can be rotated through 360° so that backwards sailing is possible.

[0029] The sail camber is controlled by the angles of the attachment booms 18 and 19 and except when moored or weather cocking when the sail is stretched flat (no camber, no drive) the fullest possible camber can be selected. The attachment booms can reduce the chord length of the sail and adjust to the fullest curvature of sail (camber) compatible with wind strength and incidence of sail to maximise forward thrust. This will depend on eventual apparent wind direction and speed. Further interacting adjustments of the sail angle and camber may then be required.

[0030] In FIG. 3 the wind direction is indicated by arrow 30. Thus the craft is head to wind, the mast is set so that the sail is also head to wind and the attachment booms are fore and aft so that the sail 5 is stretched flat and there is no camber and no drive.

[0031] In FIG. 4 the wind direction is again indicated by the arrow 30 and it will be seen that the craft is in a reaching position, that is the wind is on the beam. The mast has been rotated and the attachment booms 18 and 19 have been rotated in relation to the support structure so that the sail 5 is now cambered compatible with the wind strength and incidence of sail to provide maximum forward thrust.

[0032]FIG. 5 shows an alternative rig according to the present invention but employing two sails. The same reference numerals are used to indicate similar parts to those shown in FIGS. 1 to 4. In this construction however the fore part of the mainsail is cut back and the flexible internal spine 23 is adjacent the luff 30 of the mainsail. With this construction only the aft attachment boom 19 is retained.

[0033] The forward support member 17 is extended forward as indicated by reference numeral 31 and to the forward end of which is connected the tack 32 of a foresail or jib 33. This sail is held by a halyard 34 suitably attached to the mast 4.

[0034] The foresail 33 is attached to a self-tacking boom 35, the aft end of which is secured in well known manner to a track 36 connected to the turntable structure 11.

[0035] With this construction the mainsail 5 can again be stretched flat or suitable camber can be induced by operation of the attachment boom 19 in a similar manner to that referred to in the construction shown in FIG. 1.

[0036] The self-tacking boom will automatically adjust itself to the wind direction and the jib 33 will always be correctly located in relation to the mainsail 5 due to the self-tacking boom 35 being attached to the pivotable support structure.

[0037] Alternatively, the forward support member may be maintained at its shorter length and the fore attachment boom retained. In this event, the tack of the fore sail would be attached to the end of the fore attachment boom and the self-tacking boom would require to be of appropriate flexibility. The camber of the fore sail may then be varied similarly to that of the main sail in addition to the positional adjustment relative to the main sail provided by the self-tacking boom. 

1. A sail rig for a wind driven craft comprising a rotatable gantry mast adapted to support one or more sails within the gantry and a support structure connected to said mast to rotate therewith and which carries an aft sail attachment boom which is pivoted to the support structure at a first end and provided with means for attachment to the clew of the sail or one of the sails at its second end, and a means for controlling the relative angle of the attachment boom in relation to the supporting structure.
 2. A sail rig for a wind driven craft as claimed in claim 1 in which a single sail is employed and the support structure is provided with fore and aft sail attachment booms each of which is pivoted to the support structure at a first end and provided with means for attachment to the appropriate tack or clew of the sail at their respective second ends, and means for controlling the relative angle of each attachment boom in relation to the supporting structure.
 3. A sail rig for a wind driven craft as claimed in claim 1 in which two sails are employed which include a mainsail which is attached to the aft end of said attachment boom and a foresail which is attached to the fore part of the support structure.
 4. A sail rig for a wind driven craft as claimed in claim 2 in which two sails are employed which include a mainsail which is attached to the aft end of said attachment boom and a foresail which is attached to the fore attachment boom.
 5. A sail rig for a wind driven craft as claimed in any one of the preceding claims in which said supporting structure includes a rotatable turntable for attachment to the craft on which the gantry mast is supported and on which the attachment boom or booms are carried.
 6. A sail rig for a wind driven craft as claimed in any one of the preceding claims in which the gantry mast can be rotated through 360°.
 7. A sail rig for a wind driven craft as claimed in any one of the preceding claims in which said gantry mast has four legs.
 8. A sail rig for a wind driven craft as claimed in any one of the preceding claims in which the sail is provided with a flexible internal spine which extends between the upper part of the mast and the centre of rotation at the lower end thereof.
 9. A wind driven craft provided with a sail rig as claimed in any one of the preceding claims.
 10. A sail rig substantially as described herein with reference to and as shown in FIGS. 1 to 4 and FIG.
 5. 11. A wind driven craft substantially as described herein with reference to and as shown in FIGS. 1 to 4 and FIG.
 5. 